Active Crossover Recommendations

Peter, I've fooled around a bit with active crossovers altho with no CURRENT products. I believe:
1. You'll find virtually no difference between any 3 adjacent frequencies in your string beginning at 70; they're just too close together. IOW, there's simply not enough difference between/among 100, 115, and 120, to pick just 3. The only 3 with enough split are the last 3.
2. I strongly recommend you use a single-order slope on the hi-pass filter to the Carys and that it be a 'passive active' filter, meaning no more than a series capacitor, and a VERY-high-quality one at that. Your Cary/988 backend is probably VERY resolving, and probably you'll hear the circuitry AND the additional cables AND all the additional connections if you use an active filter. Think about how many mechanical and solder connections you'd add to the signal path with an electronic crossover!
3. I suggest you use the lo-pass filter(s) in your powered subwoofer(s).
4. I suggest you use stereo subwoofers. There is indeed directionality to bass frequencies.

IMO what you need is a soldering iron, knowledge of your amp's input impedance, and a few hi-quality caps. I suggest you experiment with crossover frequencies (=cap values) using SoniCaps. When you've decided on a frequency/capacitance, replace the SoniCap with a SoniCap Platinum or AT LEAST a Cardas Golden Ratio, the 2 finest caps I've ever heard.

So...save your money by NOT buying an electronic crossover, experiment with cap values, and enjoy superior sound thru your system. BTW I think you'll end up with a LOTS-lower hi-pass crossover frequency than 100 and above.
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Peter, I didn't go quite far enough in my comments. I believe that in a subwoofered system, one needs to run the main system as full-range as it and you can stand. With your 988s, I believe you'd increase their power-handling capacity substantially merely by removing most of the low bass from their signal. That can be done with a 40- or 50Hz hi-pass filter point; I'd start with a 50. Then set the woofers' crossover points and levels wherever you want that SOUNDS good. The point is to keep your fine-sounding main system doing about 90% of the work, and sounding GREAT at it, of course, while increasing power-handling a bit AND adding lo-bass capability. The trick will be to find PLACES for the woofers to blend well with the main system.

I've done something similar in biamping my Eminent Technology 8s. Initially I duplicated ET's c. 40Hz MR hi-pass filter point with an active filter in the amps. I then eliminated the hi-pass filter and have been running the MR panels wide open. I THINK it sounds better. At least I've eliminated the sound of one cap and its inherent phase errors.

If those 'Cary EL34 triode amps' are Rocket 88s, their 150K-Ohm input impedance would create a 48Hz filter with a 0.022µF cap.

Good luck. Pls let us know what you do.
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